The present invention relates to a method for producing decorative cast-coated papers having the appearance of decorative, uncoated papers, yet also having superior gloss and printability characteristics over uncoated papers. More specifically, the invention relates to the inclusion of flock or other particles in the coating to provide the desired decorative appearance.
The method of manufacturing undecorated cast-coated papers is well known in the art, and several variations have been employed by different artisans. All methods, however, employ certain basic steps. A paper web is passed over rollers or other coating means imparting a wet coating to one side of the paper. The wet, coated side is then passed over a heated calendering roll or cast drum, which is polished to provide a smooth casting surface and to impart a smooth finish to the cast-coated paper. Such a heated roll may be, for example, a polished chromium roll. The heated roll dries the coating on the paper, leaving the image of the smooth surface of the polished roll on the coated side of the paper. Cast-coated papers produced by this method and its variations are characterized by superior gloss properties and superior printing surfaces on the coated side. Cast-coated papers therefore also result in a superior aesthetic appeal as compared to uncoated papers.
Uncoated papers often include, for aesthetic effect, fibers, metal flakes, flock or other particles dispersed in or paper. Thus, in Beck, U.S. Pat. No. 342,315, particulate matter such as flock, tinsel, and metallic powders were applied to the surface of paper by application of mechanical pressure to embed the particles in the surface of the paper. Likewise, in Beck, U.S. Pat. No. 322,034, particles were added to paper pulp to produce desired aesthetic effects.
The coating of such papers has not proved to be desirable or efficient, though in Beck, U.S. Pat. No. 322,034, the now obsolete method of brush coating after embedding of the particles is described. Moreover, since the coatings used in the cast-coating process are somewhat opaque, coating after inclusion of particulate matter in the paper diminishes the aesthetically appealing effects achieved by inclusion of the particles in the paper. Furthermore, such particles are dispersed throughout the thickness of the paper, and do not merely appear on the surface of the paper. As a result, it is prohibitively expensive to cast-coat uncoated paper that includes particulate matter.
Metallized coated papers, such as that described in Becker et al., U.S. Pat. No. 4,567,098 are also known in the art. According to Becker et al., a metal layer is deposited upon a cast-coated paper by evaporation in vacuo. This process produces a highly polished metal surface, and does not produce a surface having flakes of metal or other particulate matter, and a different aesthetic effect is accomplished.
The inclusion of flock, fibers, metal flakes and other particulate matter in cast-coated paper has not been known in the art. Although it is known in the art that pigments may be included in the coating, it has not been known that flock, fibers, metal flakes or other particulate matter may be included in the coating to produce the desired aesthetic effects, while retaining the superior printability characteristics found generally in cast-coated papers. Cast-coated papers including flock or other particulate matter, and maintaining superior printability characteristics, may be used in conjunction with uncoated papers to produce especially desirable aesthetic effects.